Pressure generating means for deep well pumps



Jan. 27, 1959 J. E. DUBE ET AL 2,870,717

PRESSURE GENEEATING MEANS PoE DEEP WELL PUMPS Filed Aug. 15, 195:5

KNEE /s PRESSURE GEERATING MEANS FOR DEEP WELL PUMPS John E. Dube,Chesterfield, Mo., and Roger W. Schoen,

Mineral Wells, Tex., assignors to Alco Valve Company,

The present-invention relates to the pressure generating components ofdeep well pump apparatus of the type wherein the'operatio'n -of a pumpat the bottom of a well is caused by the controlling application offluid pressure lin a column of power fluid leading down from the surfacelto the pump. p

In suchfapparatuses there is a prime mover such as a gasoline or gasengine, a pump such as a vane pump which delivers primary oil underpressure, a hydraulic piston motor reciprocated by the primary oilpressure, and a hydraulic piston pump having a piston reciprocated infahydraulic cylinder connected to the power oil tubing' leading to thebottom of the well and the pump thereat. Reciprocation of the pistonproduces the pressure in the power oil required to operate the pump.Sometimes `this pressure alternates high and low; other times, such asinthe following explanation, a substantially constant pressure ismaintained in the power oil tubing.

The so-called primary oil normally is circulated from the vane pumpthrough a four-way valve alternately to the opposite ends of the powercylinder, whence it is exhausted back to the vane pump, in a closedsystem. The power oil tubing leads from a suitable supply tank at thesurface through the power oil cylinder of the pump and down tothe bottomof the well. Finally, there is a production oil line to conductproduction oil (combined with exhaust power oil) back up to the surfaceand into appropriate separators and storage tanks.

Heretofore there has been a problem in this type of pumping arisingbecause of the generation of heat in the primary oil in the closedcirculatory hydraulic motor system. Such oil tends to heat, and if ithas any vaporizable fractions in it which do vaporize, a vapor lock canoccur in the pumping system.

It is an object of the present invention to overcome the heating problemin the primary oil. It is a more specific object to overcome the heatingproblem by the use of cooling mediums that are immediately available atthe point of use so as to minimize the expense of building and operatingthe heat exchange arrangement.

Specifically, it is an object of the present invention to arrange a heatexchange device in the primary oil system which has one pass to'receivethe primary oil and another pass to receive some other cooling mediumwhich is either the production lluid coming up from the well or is thepower oil that is going down to the well. In the preferred construction,the cooling fluid is the production oil coming up from the well.

In the description to follow, reference will be made to deep wellpumping of oil. It will be understood that the invention is applicableto other fluids than oil.

ln the drawings;

Figurel is a schematic view of the surface components of'an `oil wellpump involving the present invention and wherein the cooling mediumconsists of the production oil being pumped;

ICC

Figure 2 is a similar view wherein the cooling oil is the power oil;

Figure 3 is a vertical sectional view through the heat exchange deviceshowing the two passes therein; and

Figure 4 is a horizontal section through the heat eX- change devicetaken on the line 4-4 of Figure 3. .l

` Referring first to Figure l1, a cased oil well is indi` cated at 10.It is here shown with the well tubing 11 bringing the production oil upfor delivery through a surface pipe 12. There is also a power oil pipe13 leading to a hydraulically operated pump at the bottom of the well. l

The type of pump herein involved finds many different embodiments, but atypical embodiment is that shown in the MacDougall Patent No. 2,478,410,dated August 9,1949. Other types are operated by `a substantiallyconstant pressure in the power oil line, and the pres ent descriptionwill be such a pump system.

The surface apparatus lincludes a prime mover 1S which is hereshown as agas or gasoline engine. This motor operates a vane-type primary pump 16which rotates to deliver liquid lunder pressure from an intake pipe 17to an outlet pipe 18. The pipe 18 passes through a four-way valve 19,whence it branches by a pipe 20 or a pipe 21, the two pipes leading intoopposite ends of a primary oil, hydraulic motor cylinder 22. Thecylinder 22 contains a piston 23 on a piston rod 24. The piston rodpasses through a packing gland and reciprocates in a power oil pumppiston 25 ina power oil pumping cylinder 26. This power oil pump may bereferred to as a secondary pump.

A piston rod 30 also projects oppositely from the piston 23,'outside thecylinder 22 and has a head 31 at its end.' This head operates tripmechanism 32 connected with a pilot valve 33 which is designed toreverse the four-way valve 19. Since the pilot valve is notpart of thepresent invention, it is not necessary to explain in greater detail theoperation of the pilot valve and the four-way valve. A mechanism thatmay be used is that shown in the MacDougall patent. The head 31 operatesthe trip mechanism to reverse the pilot valve and cause reversal of thefour-wayvalve, each time the pistons reach either end of their stroke.

In one position of the pilot valve 33, and hence of the four-way valve19, the pressure fluid from the pump through the line 18 passes throughthe line 20 to the left side of the piston 23, driving the piston to theright, which is made possible because the line 21 is ported to exhaustby the four-way valve. In the other position of the pilot valve 33, andof the four-way valve 19, the high pressure fluid from the pump16 passesthrough the line 21 to the right side of the piston 23 while the line 20is ported by the valve 19 to exhaust so that the piston then moves tothe left.

It will be noted that the line 13 connects into the pumping cylinder 26by two pipes 36 and 37. These two pipes contain check valves 38 and 39that admit only outflowfrom the cylinder 26 into the line 13.

The cylinder 26 is also connected by two pipes 40 and 41 to a pipe 42that leads from a power oil supply tank 43. The two branches 40 and 41are controlled by check valves 44 and 45 that admit flow only from theline 42 into the cylinder 26.

A heat exchanger 50 contains two separate fluid flow passages. It has anouter casing 51 having a top 52, a bottom 53, and a pair of headers 54and 55. A plu- -rality of tubes 56 connect through the two headers,

thereby connecting a top space 57 and a bottom space 58 and separatingthem-,from an intermediate space 59 surrounding the several tubes.

The pipe 12 enters thespace 59 which constitutes one pass of the heatexchanger, and a pipe 60 leads from the upper end of this pass 59. Thepipe 60 leads to a Separator 61 from whence another'pipe 62 leads to anoil storage tank.

,There is ;a low pressureprimary oil pipe ,63 leading from the'fourlwayvalve r19 and 'entering the 'heat exchanger 50 at the top. It passescentrally d own through the heat exchanger' andrthen opens below abaie'64 vin the bottom space 58 of the 'heat exchanger. The baffle 64ensures a spreading of the fluid. The iluid may then rise'through thetubes 56 to the top space 57, whence it may emit through the pipe 17that constitutes the intake to the vane pump. The spaces 57 and 58 andlthe' interior of the tubes 56 constitute the other pass of theexchanger.

Operation In general, the operation of the prime mover 15 and the liquidpump 16 need hardly be described since they are Well lknown in the art.See the patent to MacDougall, No.72,47.8,4l0, dated August 9, 1949.Sufce it tosay at this point that the engine rotates the pump 16 andcauses it to draw liquid through the .pipe 17 and discharge it underpressure through the pipe 18 tothe four-way valve 19. That valve isshifted by the pilot valve 33 which, in turn, -is shifted each time thepiston 23 reaches an extreme of its stroke, all as described in theMacDougall patent. The shifting of the pilot valve 33 alternately causesthe four-way valve 19 to `deliver high pressure oil from the pump 16through the pipe Ztl, or to deliver such high pressure oil through thepipe 21 at the opposite side of the piston 23. Each time one of thesetwo pipes and 21 is connected to high pressure, the other will beconnected by the fourway valve 19 to the return line 63. u 1

The primary oil in each case returns from the fourway valve 19 to thepipe 63, whence it enters the heat exchanger Sil, flowing axiallytherethrough to below the baille 6ft. Spreading around the baffle, itrises through the tubes 56 and nally flows out the pipe 17 back to thepump 16 for recirculation to the four-way valve and hydraulic motor.

As shown, high pressure primary oil is being introduced from thefour-way valve 19 through the line 20, and the piston 23 is moving tothe right, approaching its` rightwardextreme, and causing correspondingmovement of the pump piston 25 in the cylinder 26. Owing tothe presenceof the check valves 38 and 39, the rightward movement of the piston 25in the cylinder 26 drives the oil through the line 37 past the checkvalve 39 into the power oil line or tube 13. Meanwhile, the check valveprevents the egress of ltheaforesaid oil back into the supply line 42.Appropriate relief means against excess pressure in the pipe 13 may beprovided.

Rightward movement of the piston 25 also draws oil in from the supplyline 42 past the check valve 44, and bythe pipe di) to the left side ofthe piston 25. During this, the check valve 38 prevents the drawing ofoil from the pipe 13 to the left side of the piston.

Rightward movement of the two `pistons occurs in corresponding manner,upon shift of the valves 33 and 19. In other words, the piston 25constitutes a twoway pump which maintains substantially continuouspressure on the oil in the pipe 13. It will be vunderstood that aone-way alternate high pressure and low pressure pumping system may beused where that is the type of deep well pump involved. The presentarrangement, however, is used where the deep well pump requires constanthigh pressure on the power oil.

The deep well pump within the well 10 brings oil up and discharges itthrough the pipe 12. From this pipe it enters the intermediate pass 59of the heat exchanger. Being cold, it withdraws heat from the primaryoil that is circulating through the tubes 56. The production oil leavesthe heat exchanger by the pipe 60, thence moves throughua separator 61from which i As illustrated in Figure 2,the cooling of the primary oilmay also be obtained by passing the power oiliustead of the productionoil through the heat exchanger. Figure 2 shows the prime mover 15 andthe pump 16 as before. The pump delivers to the four-way reversing valve19 just as before, and this valve controls -the llow to the hydraulicvpiston motor cylinder 22, just asbefore. This motor operates the pumppiston, not shown, but contained within the cylinder 26 just as beforeso .as to maintain substantially constant high pressure on tbe` poweroil pipe 13. The production oil pipe 12 brings oil up and, in this case,delivers it directlyto the Separator.

'The heat -exchanger '50 is the same as before. However, the power oilpipe 142 delivers power oil into the intermediate pass of the heatexchanger, and it emits from that pass by the pipe and flows intothe op`posite end of the cylinder 26. In other words, in the present case theintermediate pass of the heat exchanger 50 has been interposed into thepipe leading from lthe -power oil supply tank to theoppositeends of thepump cylinder 26. The other pass of the heat exchanger receives primaryoil from the pipe 63, that is the exhaust side of the four-way valve,and it delivers oil ,through the pipe 17 that leads tothe intake side ofthe vane motor `16, all just `asin Figure 1.

The only diierence of Figure 2 over Figure 1, therefore, is that insteadof passing the production oil through the intermediate pass of the heatexchanger 50, as in Figure 1, the power oil fromthe power oil tank is-run through this intermediate pass in Figure 2. The operation of thesystem is the same as before, save only that the power oil does theAcooling of the primary oil, and'is itself increased in temperaturesomewhat. This latter is immaterial because the power oil will be cooledwhen it descends into the earth through thewell;

It willV be seen that in `both exemplications of` this invention theprimary oil which is used to operate the hydraulic motor is kept fromheating excessively and f perhaps foaming or'vaporizing, because of thepresence of the heat exchanger. It'also is apparent that the heatexchanger derives its source of coldfrom an immediately available supplyoffluid such` as the production oil delivered from the well or the poweroil delivered to the well.

vWhat is claimed is: k Y

1. In a well pumping apparatus: a fluid circuitincluding a primary uidpump, a iluid motor, connections between the pump andthe fluid motor sothat the iluid pressure produced by `the :pump operates the iluid motor,and connectionsy from' the iluid motor back to the pump whereby the-fluid can be circulated kin a closed system; a fheat exchanger havingtwo passes, one

pass interposed .in one of said connections; a second-k ary pumpconnected with and adapted to `be .operated by the fluid motor; poweruid piping connecting-into the last named pump; power oil vhigh pressurepiping leading from the last named pump, ak deep well pump connected tothe power oil high pressure piping at the bottom of a well;y aproduction fluidpiping for conducting production uid from the pump; andconnections introducing one of said last named fluid piping's throughthe other pass of the heat exchanger.

y2. The combination of claim 1,1171 which the production uid piping isthe one 'of the pipings lconnected to the heat exchanger.

3. The combination of claim 1, in which the power uid piping is the oneof the pipings connected through the heat exchanger.

4. In a well pumping apparatus: a prime mover; a primary hydraulic pumpoperated by the prime mover; a hydraulic piston motor, a heat exchanger;connections from the heat exchanger to the primary pump; connectionsfrom the primary pump to the opposite sides of the hydraulic pistonmotor, with reversing valve means in said last-named connectionsalternately to connect one side of the piston to the high pressure sideof the primary pump and correspondingly to connect the opposite side ofthe piston to the heat exchanger; a hydraulic secondary pump connectedto and operated by the hydraulic piston motor; piping connect- 152,478,410

References Cited in the le of this patent UNITED STATES PATENTS1,860,137 Carr May 24, 1932 2,033,210 Tennant et al. Mar. 10, 19362,429,947 Rose Oct. 28, 1947 2,432,079 Albert Dec. 9, 1947 MacDougallAug. 9, 1949

